What is the Hard Problem of Consciousness & Why is It Difficult?

[Bartholomew]

"non-linear" devices which exhibit all the properties of non-linear dynamics: ergodic behavior, catastrophe, sensitive dependence, attractors, bifurcation, chaos, and fractal geometry

All of those things you describe can be done, have been done, and are being done on computers.

 

[Les Sleeth]

Well, you could have mentioned the termites as that's the finest example in the book and a little more impressive than fire-flies.

No slight intended, I am very impressed with the organizational abilities of certain life forms and agree with you fully there. I simply quoted what the book reviewer chose to talk about.

I believe we have "examples" of the "capability" of matter organizing into precursors of life: Miller was the first to show that amino acids could be created from pre-biotic chemicals (water, ammonia, methane, few more). At high temperature, amino acids spontaneously assemble into polymers called thermal-proteins which upon cooling, produce cell-like structures called microspheres. Pre-cursors of nucleic acids (purines and pyrimidines) have been synthesized from hydrogen cyanide and other chemicals under suspected pre-biotic conditions. . . . Also, I'm finding out you guys have been discussing this subject at length in the Epistemology section which I've just begun to look at.

In the 2 1/2 years I've been debating this issue here at PF, the Miller-Urey experiment was cited every time by opponents, and the other organic potentials much of the time (sometimes they list synthesized phages as examples, though they tend to leave out that DNA was tossed into the kettle). That's how little progress has been made toward demonstrating matter can self organize itself into life since the 1950s.

The thing is, if there is an unrecognized organizational principle that worked with Earth's chemistry to produce life, the raw materials need to be somewhat predisposed to being organized. So it would not be unusual for some degree of spontaneous "mechanomorphic" organization to happen. But those few steps chemistry is capable of doesn't represent what happened, and happens, with life. There organization kept going, and going, and going . . . it is still going. Further, it wasn't just order that the organization produced, it was functioning systems which could operate in support of new systems that would be built on top. Matter alone has never been shown it can act that way spontaneously or even be kicked into "self-organizing gear" with lots of help from scientists.

So I feel my skepticism is justified, and not due to a priori convictions such as those by physicalists who insist matter is alone is the creator of life without enough evidence to make their case.

Computers today are "linear" in my view, mostly "look-up" tables made up of transistors operating in their linear ranges (pretty sure about the transistors anyway). Someone someday is going to come up with "non-linear" devices which exhibit all the properties of non-linear dynamics: ergodic behavior, catastrophe, sensitive dependence, attractors, bifurcation, chaos, and fractal geometry. You'd think that would be a mess at first and I suspect the first workings would exhibit peculiar forms of "cognition" that we're not acustomed to. It's there I think we'll start to formulate better ideas of what mind is.

I agree the research is exciting. Even though I don't believe independent and conscious subjectivity will emerge from it, what AI could produce should be impressive.

 

[saltydog]

All of those things you describe can be done, have been done, and are being done on computers.

But I think they're only being simulated on a computer screen. It's like watching a TV program. The images look like people but really aren't.

SD

 

[saltydog]

The thing is, if there is an unrecognized organizational principle that worked with Earth's chemistry to produce life, the raw materials need to be somewhat predisposed to being organized. So it would not be unusual for some degree of spontaneous "mechanomorphic" organization to happen. But those few steps chemistry is capable of doesn't represent what happened, and happens, with life. There organization kept going, and going, and going . . . it is still going. Further, it wasn't just order that the organization produced, it was functioning systems which could operate in support of new systems that would be built on top. Matter alone has never been shown it can act that way spontaneously or even be kicked into "self-organizing gear" with lots of help from scientists.

In defense of Chemistry, even one reaction can be difficult to study.

Has Stuart Kaufmann been mentioned in these discussions? He proposes a revolutionary idea: catalytic closure. In essence, primitive RNA arose which had catalytic ability to assist with protein formation. Through selection, some protein chains arose which had catalytic ability to assist in RNA synthesis. At this point the RNA-protein system becomes synergistic and in some ways self-organizing. I realize it's a theory but it's based on reasonable chemical principles.

An Idea:

With regards to increasing complexity: As the diversity of form (molecules, life-forms, habitats, etc.) increases, the number of degrees of freedom increases. This necessarily increases the dimension of the system's state space (space of all possibilities). Enlarging the state-space this way allows access to a greater variety of high-dimension "attractors" (islands of stability). I propose that what we see as increasing complexity is actually a trajectory from low dimension attractors to high dimension attractors (attractors within attractors) made possible by an influx of energy (sun, chemical bonds) and increasing diversity. Thus, similar to the marble-analogy, if a system is designed in which it's degrees of freedom increases (greatly), a suitable dynamics (with influx of energy) can be defined within the system which will have similar characteristics to the evolution of complexity on earth. At present, we're just too limited in our sophistication to model this. I mean, math is really at it's infancy now-days (no offense, I have a passion for math).

SD

 

[Les Sleeth]

Has Stuart Kaufmann been mentioned in these discussions? He proposes a revolutionary idea: catalytic closure. In essence, primitive RNA arose which had catalytic ability to assist with protein formation. Through selection, some protein chains arose which had catalytic ability to assist in RNA synthesis. At this point the RNA-protein system becomes synergistic and in some ways self-organizing. I realize it's a theory but it's based on reasonable chemical principles.

Yep, just theory. And you really don't know if that combination of principles is "reasonable." If someone can make it work, then it was reasonable; if not, then it wasn't. Demonstrate it, and then we have something to talk about.

With regards to increasing complexity: As the diversity of form (molecules, life-forms, habitats, etc.) increases, the number of degrees of freedom increases. This necessarily increases the dimension of the system's state space (space of all possibilities). Enlarging the state-space this way allows access to a greater variety of high-dimension "attractors" (islands of stability). I propose that what we see as increasing complexity is actually a trajectory from low dimension attractors to high dimension attractors (attractors within attractors) made possible by an influx of energy (sun, chemical bonds) and increasing diversity. Thus, similar to the marble-analogy, if a system is designed in which it's degrees of freedom increases (greatly), a suitable dynamics (with influx of energy) can be defined within the system which will have similar characteristics to the evolution of complexity on earth.

Interesting theory. You'll have to demonstrate it if you want to talk about it as fact.

At present, we're just too limited in our sophistication to model this. I mean, math is really at it's infancy now-days (no offense, I have a passion for math).

Everybody says they need more time to prove their theory is true. Creationists need more time to find the Garden of Eden and Noah's Ark.

It is possible that the reason you cannot make your case now is because you will never be able to make your case. Physicalists can't insist we accept they will eventually discover the truth based on their faith in empiricism to reveal all revealable truths! I don't share that faith, and lots of other thinking people also do not. I am open to a physicalist proof, but I ain't budging from my skepticism until I see progress in the areas of abiogenesis and physically-derived consciousness.

 

[saltydog]

It is possible that the reason you cannot make your case now is because you will never be able to make your case. Physicalists can't insist we accept they will eventually discover the truth based on their faith in empiricism to reveal all revealable truths! I don't share that faith, and lots of other thinking people also do not. I am open to a physicalist proof, but I ain't budging from my skepticism until I see progress in the areas of abiogenesis and physically-derived consciousness.

Ok. I've exhausted my comments about the matter and besides, I think I've gotten off the subject of the initial posting. Suppose I'll go back to differential equations. I think I can be of practical help to the group there.

Well . . . a question: I made the following statement elsewhere here attempting to define existence in relation to Decartes' comment:

<br /> Existence \notin \varnothing<br />

Yes, no, off-the subject? Anyone?

SD

 

[cen2y]

Existence \notin \varnothing

Whether your notion is wrong or not depends on what logical system you use to declare that. According to my ontology
Existing\ objects \notin \varnothing
i.e.
Things\ which\ possess\ the\ property\ of\ existence \notin \varnothing
\forall(x)(Existing(x) &lt;=&gt; x \notin \varnothing)
Which is quite obivious since writting out 'existence' is inessential.

 

[Photongod]

boot strapping of the mind

Sage asked:
what exactly is the hard problem of consciousness? why is it hard?

Perhaps the difficulty lies with a problem of self reference. In order to study ones consciousness, one must use his/her consciousness to do so . This leads to a set of obvious problems of interference and gridlock.

Photongod

 

[Problem+Solve=Reason]

This leads to a set of obvious problems of interference and gridlock.

Not exactly. We (our consciousness let's say) study our (itself) consciousness by things that have been affected by our consciousness, not the actual entity itself.

____________________________________
In seeking wisdom thou art wise; in imagining that thou hast attained it - thou art a fool.
Lord Chesterfield

 

[selfAdjoint]

Yep, just theory. And you really don't know if that combination of principles is "reasonable." If someone can make it work, then it was reasonable; if not, then it wasn't. Demonstrate it, and then we have something to talk about.

Type catalytic+closure+experiment but not cognitive into google scholar and get over 2100 responses, most of them reports of experiments that found, studied or confirmed it. Les you get away with murder here with your handwaving dismissals of things you evidently know only slightly.

 

[philocrazy]

loseyourname


Do you believe that absolutely everything can be expressed scientifically?
-Hedwig Born to Albert Einstein

Yes, it would be possible, but it would make no sense. It would be description without meaning, as if you described a Beethoven symphony as a variation of wave pressure.
-Einstein's reply
====================================
would + would = 2 woulds + would =3 woulds (sounds like science to me)
what does it say?=nothing (description without meaning)
sound is a variation of wave presure and beethoven symphony when
heard is also a variation of wave presure
everything can be expressed philosophically and with meaning

The myth

 

[Les Sleeth]

Type catalytic+closure+experiment but not cognitive into google scholar and get over 2100 responses, most of them reports of experiments that found, studied or confirmed it. Les you get away with murder here with your handwaving dismissals of things you evidently know only slightly.

I regretted being so negative after seeing Saltydog say "Suppose I'll go back to differential equations." I was in the warpath over theories stated like facts. In his case it stemmed from his opening statement "Consciousness is in the dynamics. It's nothing more than neural dynamics. Get a bunch of marbles behaving in the same non-linear fashion as neural assemblies and marble mind will emerge." However, he'd backed off from that, and was discussing things fairly yet I kept pushing the point. I am sorry for that.

However, while I don't think my attitude was called for, my response to his statement was factually correct. I know of Kauffman's work and have his book "The Origins of Order." I can't say I understood every bit of his book (it's been a few years since I read it), but I do know his perpetual autocatalytic hypothesis is another abiogenesis theory no one can prove will lead to "livingness."

So when Saltydog posted, "In essence, primitive RNA arose which had catalytic ability to assist with protein formation. Through selection, some protein chains arose which had catalytic ability to assist in RNA synthesis. At this point the RNA-protein system becomes synergistic and in some ways self-organizing," I was stating that is abiogenesis theory, not fact. I stand on that.

 

[saltydog]

I regretted being so negative after seeing Saltydog say "Suppose I'll go back to differential equations." I was in the warpath over theories stated like facts. In his case it stemmed from his opening statement "Consciousness is in the dynamics. It's nothing more than neural dynamics. Get a bunch of marbles behaving in the same non-linear fashion as neural assemblies and marble mind will emerge." However, he'd backed off from that, and was discussing things fairly yet I kept pushing the point. I am sorry for that.

Well, that was hard Les. I admire your wisdom sir. I'd like to think I didn't back-off the marbles, just can't prove something I believe in (I'm thinking 300 years for the boot). And I really love differential equations but find myself here more often than not. Thanks.

Salty

 

[selfAdjoint]

So when Saltydog posted, "In essence, primitive RNA arose which had catalytic ability to assist with protein formation. Through selection, some protein chains arose which had catalytic ability to assist in RNA synthesis. At this point the RNA-protein system becomes synergistic At this point the RNA-protein system becomes synergistic and in some ways self-organizing," I was stating that is abiogenesis theory, not fact. I stand on that.

Agreed that's just a hypothesis ("just a theory" is technically wrong and sounds too much like the creationists). You are absolutely right there and as far as you limit yourself to that issue I have no argument.

But lots of things the consciousness dualists assert are just hypotheses too. Sauce for the goose? Example, the claim in that book they're studying, that science is "just differences" that you can add up and totalize is contradicted by catalytic closure in chemistry, populations, and cellular dynamics.

 

[Canute]

But lots of things the consciousness dualists assert are just hypotheses too. Sauce for the goose? Example, the claim in that book they're studying, that science is "just differences" that you can add up and totalize is contradicted by catalytic closure in chemistry, populations, and cellular dynamics.

The claim that science is the study of bare differences has nothing to do with dualism as far as I can tell. It's just a fact, or put forward as one. What makes you say that chemistry, cellular dynamics and so on contradict that claim? I can't see the connection.

 

[selfAdjoint]

In the 2 1/2 years I've been debating this issue here at PF, the Miller-Urey experiment was cited every time by opponents, and the other organic potentials much of the time (sometimes they list synthesized phages as examples, though they tend to leave out that DNA was tossed into the kettle). That's how little progress has been made toward demonstrating matter can self organize itself into life since the 1950s.

Following quote is from a semitechnical account of Venters artificial virus creation, in November 2003.

To create the virus, the researchers first assembled single nucleotide bases into DNA based on the virus' known genetic sequence. An enzyme then transcribed the DNA into the single-stranded RNA genome. The virus could then replicate itself naturally.

The DNA that was "thrown into the kettle" was created by hand from single bases.

The claim that science is the study of bare differences has nothing to do with dualism as far as I can tell. It's just a fact, or put forward as one. What makes you say that chemistry, cellular dynamics and so on contradict that claim? I can't see the connection.

Catalytic Closure is an emergent property that cannot be reached by adding up the elementary processes that comprise it. There is a random component. Catalytic closure has been SHOWN to occur in chemical and other contexts, as the google search I suggested above will show you. This contradicts the assertion that physical nature is just bare differences and falsifies the "fact" that you assert.

 

[Photongod]

said:

Not exactly. We (our consciousness let's say) study our (itself) consciousness by things that have been affected by our consciousness, not the actual entity itself.

Could you give me an example?

It still sounds like a nose trying to smell itself to me. Photongod

 

[Les Sleeth]

The DNA that was "thrown into the kettle" was created by hand from single bases.

Keep in mind I was responding to claims of chemistry's self-organizing ability. In this case, I was referring to the argument that all you have to do to produce a phage is throw a bunch of chemicals in a vat and you get one (I think it was Psychodelerium who first put it that way to me), and therefore it is an example of extended self organization by chemistry. But as you know, there is significant assembling done ahead of time (plus, included in the materials needed for PCR is typically genomic DNA), and so it doesn't demonstrate the ability of chemistry to self organize itself from scratch into bacteriophages.

The consciously unassisted self-organizing ability of chemistry was my point, not that scientists aren't doing clever things with biochemistry. I am claiming that chemistry's demonstrated self-organizating potential falls significantly short of what it would take for abiogenesis (or for viruses to self organize from raw materials).

 

[selfAdjoint]

I am claiming that chemistry's demonstrated self-organizating potential falls significantly short of what it would take for abiogenesis (or for viruses to self organize from raw materials).

Some spontaneous chemical self-organizations in 1994:
http://www.iupac.org/publications/pac/1994/pdf/6610x1961.pdf

 

[Les Sleeth]

Some spontaneous chemical self-organizations in 1994:
http://www.iupac.org/publications/pac/1994/pdf/6610x1961.pdf

I haven't denied what self-organizing potential has been demonstrated, and certainly polymers and amino acids are examples. But as I pointed out earlier to Saltydog:

". . . those few steps chemistry is capable of doesn't represent what happened, and happens, with life. There organization kept going, and going, and going . . . it is still going. Further, it wasn't just order that the organization produced, it was functioning systems which could operate in support of new systems that would be built on top. Matter alone has never been shown it can act that way spontaneously or even be kicked into [that sort of] "self-organizing gear" without lots of help from scientists."

So it is a specific quality of self organization that cannot be demonstrated, not that self organization cannot happen at all.

BTW, what's wrong with the idea there might be an undiscovered organizing principle? Nobody minds considering the possibility of the theoretical Higgs particle, or dark matter, or any other thing that helps explain things.

 

[loseyourname]

Catalytic Closure is an emergent property that cannot be reached by adding up the elementary processes that comprise it. There is a random component. Catalytic closure has been SHOWN to occur in chemical and other contexts, as the google search I suggested above will show you. This contradicts the assertion that physical nature is just bare differences and falsifies the "fact" that you assert.

I think Gregg is right to say that physics is the study of relational properties that don't need to be instantiated for physics to be coherent. His analogy between a pure Life world and a pure physical world is dubious if taken literally, but I don't think he meant it that way and I can see why he uses a Life world as an illustration. Perhaps the facts of all other sciences are entailed by these facts of physics - they certainly seem to be. I do know, however, that many of the phenomena studied by other sciences are strongly emergent and cannot be deduced statically from facts of physics. This is especially true of the social and behavioral sciences. I'm having a hard time getting hypnagogue to agree to this, though.

The phrase "bare differences" may not be the best way to describe physical quantities. I've never liked it myself, because physics can certainly study the relations of phenomena that are exactly the same, potentially even in exactly the same state. The thing is, entailment to me doesn't mean the potential to be logically deduced from lower-level physical facts. It just means that a given output is the result of a given input, even if you can potentially get many different outputs and the result is in many ways random.

 

[selfAdjoint]

I suspect that the bare differences was chosen for rhetorical effect, but it does artificially narrow his focus, and just isn't convincing to someone who has a rich background in science. I for one would wonder how he would impose bare differences on topology. How is the difference between a sphere and a torus "bare"

 

[selfAdjoint]

I haven't denied what self-organizing potential has been demonstrated, and certainly polymers and amino acids are examples. But as I pointed out earlier to Saltydog:

". . . those few steps chemistry is capable of doesn't represent what happened, and happens, with life. There organization kept going, and going, and going . . . it is still going. Further, it wasn't just order that the organization produced, it was functioning systems which could operate in support of new systems that would be built on top. Matter alone has never been shown it can act that way spontaneously or even be kicked into [that sort of] "self-organizing gear" without lots of help from scientists."

So it is a specific quality of self organization that cannot be demonstrated, not that self organization cannot happen at all.

I would distinguish "has not been demonstrated" from "cannot be demonstrated"

BTW, what's wrong with the idea there might be an undiscovered organizing principle? Nobody minds considering the possibility of the theoretical Higgs particle, or dark matter, or any other thing that helps explain things.

Well, self-organized criticality IS a new organizing principle; it has taken off because it has testable consequences. People can see it happening. It is also a clear idea that people can grasp, something rare and precious in science .

The article on spontaneous chemical assemblies I linked to is part of a research program in chemistry called the supermolecular program. Since it is demonstrated that SOME chemicals will spontaneously react to form more complex molecules, they have worked to find rational ways to specify what those some chemicals might be. Just as autocatalysis requires patters of internal interactions to work, so these researchers find "algorithms" encoded in the moleculare reactivities which they can follow up. Some of this, while admirably ingenious, seems a little pedestrian to me. Quantum theorists studying self-organization have stronger tools in their kits - renormalization group theorems for example.

Of course you have adopted the "Naw that ain't it" stance, and "that" won't ever be "it" until Galatea rises from the inert chemical bath in that kettle.

 

[Les Sleeth]

Of course you have adopted the "Naw that ain't it" stance, and "that" won't ever be "it" until Galatea rises from the inert chemical bath in that kettle.

Well, I thought you offered a collegial olive branch a few dozen posts ago. Since then, I've not descended into ridicule of your skepticism about what I have come to trust, nor directly confronted you about your beliefs.

To me, collegial means respecting what has convinced another of something; and then, if we are to disagree, it is in the spirit of mutual respect. Those comments above feel like ridicule. Do you really think the basis of my skepticism is a moronic "naw that ain't it"?

Why not put the shoe on the other foot? Are you ready to buy centuries of introspectionists' reports of "something more," along with my testimony, and abandon your own skepticism? My skepticism is not due to a priori beliefs as yours seem to be. I don't "believe" in God and I don't "believe" in the potential of physicalness to self organize itself into a cell (and even less into consciousness). Why?

In the case of God, all I have is an inner "feel" for something that I've experienced many years from mediation. To be fully accurate, there isn't enough information in that experience (not yet anyway) to make me certain that the "something more" is God. If you aren't going to try that experience for yourself, then you aren't going to understand what confidence I have there is "something more" going on behind reality than just physics.

In the case of physicalness being the "creator," I don't see the right evidence in a couple of crucial places. I can imagine a dumb cell might be purely physical, but the self-organizing ability to make it into a cell is not showing itself in physicalness. Physicalist "believers" in my opinion are suffering from the same blind faith they are down on the religious for indulging in. All the examples given for why someone should have faith in matter's self organizing potentials are smoke. No one is even close to demonstrating it, but the a priori commitment to physicalism seems to make people gloss over this huge missing piece.

As for me, since I don't care one iota what the truth turns out to be, I remain free to believe what the evidence indicates (including my inner experience), and to remain skeptical of the exaggerations of "believers."

 

[Canute]

I suspect that the bare differences was chosen for rhetorical effect, but it does artificially narrow his focus, and just isn't convincing to someone who has a rich background in science. I for one would wonder how he would impose bare differences on topology. How is the difference between a sphere and a torus "bare"

It wasn't for rhetorical effect, it is the basis of his argument against physcalism. What he is saying, as Loseyourname said, is that physics studies the relations between things, not the things themselves. In other words, physics has no grounding ontology.

This is equivalent to saying that the universe of subjects and objects has only a dependent existence or, more scientifically, as Bohm and others argue, that it is in effect a hologram. I don't know Bohm well but perhaps one could say that physics studies what is explicate, not what is implicate. Note also that in M-theory there is a sense in which spacetime, and thus all it contains, does not exist. Physics has yet to identify any absolute substance or entity. In more philosophical terms we could say that we still cannot see beyond appearances, or out of Plato's cave, or solve the problem of attributes (of what exists other than appearances).

This is what the issue of bare differences is about. What GR is saying is that physics cannot provide a complete ontological account of the universe, an account of what things actually are, because it studies only the difference between things, not the things themselves. These differences are 'bare' in the sense that they are not ontological differences but simply differences in the appearance of things. In a way this is just a restatement of the 'hard problem' in a different form. GR relates this to the problematic ontology of conscious experience, but it is just relevant to the problematic ontology of matter and energy.

On the biology/life question you might be interested in Varella's work on autopoetic systems. He examines their structure and emergence in the light of the mathematics of George Spencer-Brown, which is founded on the proposition that such structures arise from and consist of, in effect, just bare differences.

 

[saltydog]

Some spontaneous chemical self-organizations in 1994:
http://www.iupac.org/publications/pac/1994/pdf/6610x1961.pdf

Thanks for the reference SelfAdjoint. My background is in Chemistry so I'll feel at home.

Salty

 

[saltydog]

BTW, what's wrong with the idea there might be an undiscovered organizing principle? Nobody minds considering the possibility of the theoretical Higgs particle, or dark matter, or any other thing that helps explain things.

I believe their are and am optimistic future generations will discover them. To avoid redundancy, I won't bring up the banner in the dojo again.

 

[Tournesol]

How do you get from non-linear (or any other) kind of behaviour to qualia ?

 

[selfAdjoint]

It wasn't for rhetorical effect, it is the basis of his argument against physcalism. What he is saying, as Loseyourname said, is that physics studies the relations between things, not the things themselves. In other words, physics has no grounding ontology.

This is equivalent to saying that the universe of subjects and objects has only a dependent existence or, more scientifically, as Bohm and others argue, that it is in effect a hologram. I don't know Bohm well but perhaps one could say that physics studies what is explicate, not what is implicate. Note also that in M-theory there is a sense in which spacetime, and thus all it contains, does not exist. Physics has yet to identify any absolute substance or entity. In more philosophical terms we could say that we still cannot see beyond appearances, or out of Plato's cave, or solve the problem of attributes (of what exists other than appearances).

This is what the issue of bare differences is about. What GR is saying is that physics cannot provide a complete ontological account of the universe, an account of what things actually are, because it studies only the difference between things, not the things themselves. These differences are 'bare' in the sense that they are not ontological differences but simply differences in the appearance of things. In a way this is just a restatement of the 'hard problem' in a different form. GR relates this to the problematic ontology of conscious experience, but it is just relevant to the problematic ontology of matter and energy.

On the biology/life question you might be interested in Varella's work on autopoetic systems. He examines their structure and emergence in the light of the mathematics of George Spencer-Brown, which is founded on the proposition that such structures arise from and consist of, in effect, just bare differences.

Thanks for the explanation Canute. I do grant this aspect of science, and my own belief is that the "ding an sich" is just as much a myth as the homonculus. I can't follow the reasoning that says "since empirical study of the world does not supply us with an ontology, let us derive one by thinking abstractly about consciousness". That is a traditional way to go of course (Hegel and successors) but I have never seen it lead anywhere productive.

 

[Canute]

Thanks for the explanation Canute. I do grant this aspect of science, and my own belief is that the "ding an sich" is just as much a myth as the homonculus. I can't follow the reasoning that says "since empirical study of the world does not supply us with an ontology, let us derive one by thinking abstractly about consciousness". That is a traditional way to go of course (Hegel and successors) but I have never seen it lead anywhere productive.

I'm guessing that "ding an sich" is thing-in-itself. If so then doesn't there have to be at least one thing that is a thing in itself? It seems to me that most things can have no 'in themselves' existence, as you suggest, and have only a dependent existence, but not absolutely everything, otherwise nothing could exist.

Like you I also can't follow the reasoning of the sentence you give. We cannot see the 'in itself' aspect of consciousness by thinking abstractly about it, so to do so will tell us no more about ontology than thinking abstractly about electrons, quarks or branes (or God). All we are thinking about are 'bare differences'. However consciousness is 'what it is like', and as such is the one thing that we can explore without thinking abstractly about it. So in this respect it seems that we can know it as a thing in itself and therefore can, in principle at least, derive an ontology from it.